Scraper control system



p 1965 H. w. ROCKWELL ETAL 3,206,880

SCRAPER CONTROL SYSTEM 3 Sheets-Sheet 1 Filed Oct. 50, 1962 Fin mm P1965 H. w. ROCKWELL ETAL 3,206,880

SCRAPER CONTROL SYSTEM 3 Sheets-Sheet 2 Filed 001;. 30, 1962llllllllllllllllllllllllllll Q 9 W MHM w. m M

United States Patent 3,206,880 SCRAPER CONTROL SYSTEM Harvey W. Rockwelland Reynold M. Anderson, Cedar Rapids, Iowa, assignors to Allis-ChalmersManufacturing Corporation, Milwaukee, Wis.

Filed Oct. 30, 1962, Ser. No. 234,099 6 Claims. (Cl. "37-429) Thisinvention relates to a control system for hydraulic jacks of an earthmover or scraper. More particularly, this invention relates to a remotecontrol system for hydraulic jacks which operate various materialhandling components of the earth mover.

Heretofore it has been the common practice in earth moving motor scrapercontrols to provide control valves at the operators station andappropriate hoses to the hydraulic jacks employed to raise and lower thecutting edge, eject material and control the apron. Thus for the threeusual functions of ejecting, apron control and raising and lowering ofthe bowl, as many as four different lines were required to pass from theoperator station on the tractor to the trailing scraper.

The control system described herein improves upon prior systems in anumber of aspects. This invention employs a single supply passage toseries connected valves. Only one supply hose and one return toreservoir hose passes between the tractor unit and trailer unit. Also abypass passage with diverter valve is employed between the high pressureand low pressure sides of the system to reduce the work required by thepump and to reduce pump wear.

It is an object of this invention to provide an improved hydrauliccontrol system for an earth mover.

It is a further object of this invention to provide an improvedhydraulic control system for an earth mover wherein the control valvesare located near the hydraulic jacks they control, are connected inseries by a supply passage and only one supply hose and one return hosepasses between the source of hydraulic fluid and the portion of theearth mover on which the jacks are employed.

It is a further object of this invention to provide a scraper controlsystem which has simplified hydraulic circuits, has minimum fluidcirculation power losses, has quick response to operator control, andwhich automatically unloads the pump when high pressure fluid is notrequired to actuate the jacks.

It is a further object of this invention to provide an electricallycontrolled system for remote hydraulic valves wherein a diverter valveis automatically controlled by the electric control system to unload thepump when hydraulic fluid is not required by the jacks.

It is a further object of this invention to provide an improvedhydraulic control system for an earth mover wherein an electric over aircontrol arrangement is employed to operate hydraulic valves locatedremote from the operator station.

These and other objects of this invention will be apparent when thefollowing description is read in conjunction with the drawings in which:

FIG. 1 is a top view of an earth mover in which the present invention isutilized;

FIG. 2 is a side view of the earth mover illustrated in FIG. 1;

FIG. 3 is a schematic showing of the control system of this invention;

FIG. 4 is a section view of the bowl and apron control valves;

FIG. 5 is a section view of the ejector control valve; and

FIG. 6 is a section view of the diverter and relief valves.

Referring to FIGS. 1 and 2, the earth mover is made up of a fronttractor unit 11 and a motorized trailer unit 16. The front tractor unitincludes an engine 51 driving front wheels 15 and an operator station 12at which a steering wheel 13 and operator seat 14 are located. Thetrailer unit 16 includes a yoke 17 which is pivotally connected to thefront tractor unit by hitch means permitting horizontal swingingmovement of a front tractor unit about a vertical axis and lateraloscillating movement of the front tractor relative to the yoke 17.Steering of the front tractor unit relative to the yoke 17 about avertical pivot axis is accomplished by steering means 19. The trailerunit 16 also includes a bowl structure 18 pivotally connected to theyoke 17 on a transverse axis 21. The bowl structure 18 includes atransverse blade structure 30, side walls 24, 25 and rear driving wheels27 driven by the rear engine 20.

Material is ejected from the earth mover bowl structure by actuation ofa hydraulic motor in the form of an ejector jack 31 to thereby pivot thebottom 28 about its pivot connection 29 with blade structure 30. Thejack 31 is pivoted at its bottom end to a transverse frame member ofbowl structure 18 and is pivoted at its top end to the pivoted bottom28. The bowl structure 18 is raised and lowered by a pair of hydraulicmotors in the form of bowl control jacks 32 which are pivotallyconnected at their lower rod ends to the forward end of side walls 24,25, and are pivotally connected at their upper ends to the yoke 17. Theapron 33 is pivot-ally connected to the side walls 24, 25 for pivotalmovement about the axis of pin 34. The apron is pivoted by a hydraulicmotor in the form of an apron control jack 36 pivoted at its lower endto the yoke and at its upper end to a lever 37 which carries a sheaveabout which an apron control cable 38 is reeved. Control valve assembly41, containing the bowl control valve and the apron control valve, ismounted on the yoke in close proximity to the jacks 32, 36 controlledthereby. Ejector control valve assembly 42 is mounted on the bowlstructure 18 in close proximity to the ejector jack 31.

The control valve assemblies 41, 42 are operated by an electric over airsystem, the electric control switches of which are mounted on a terminalblock 46 at the operators station 12 which includes a handle 47permitting the operator to steady his hand during operation of themanually operated elements or switches with his thumb or fingers. Adiverter valve 48 is mounted on a hydraulic reservoir 49 carried by thetractor unit 11.

Referring to FIG. 3 showing the schematic showing of the electric overair over hydraulic control system, the engine 51 of the front tractorunit drives a hydraulic pump 53 and an air compressor 50 the latter ofwhich supplies compressed air to an air storage tank 55. The hydraulicpump 53 draws fluid from the hydraulic reservoir 49 and suppliespressure fluid to the high pressure side of the system which includes afluid supply passage 54 which passes through the bowl and apron controlvalve assembly 41 and to the ejector valve assembly 42. The low pressureside of the hydraulic system includes a return to reservoir passage 56which connects valve assembly 42 to the reservoir 49 and a branchpassage 57 connected to valve assembly 41. A bypass passage 58 isconnected at one end to the reservoir 49 and at its other end to thesupply passage 54 intermediate the pump 53 and the control valveassemblies 41, 42. A diverter valve 48 is interposed in the bypasspassage 58 and the housing 59 therefor also houses a relief valve 61which is hydraulically in parallel with the diverter valve 48.

The control valves of this control system are pilot operated bycompressed air controlled by electrically operated air valves. An airconduit 64 supplies compressed air to a pneumatic actuator 66 employedto assist in opposite ends of valve assembly 42. Branch conduits 158,

191, 192, 193 connect conduit 63 'to air valves at opposite ends of thetwo spools of valve assembly 41. Air conduit 82 connects conduit 63 toan air valve 81.0n diverter valve 48. The electrical control system foroperating the electrically controlled air valves is connected to theearth mover electrical system through a switch 86. The electrical powersource is illustrated as a battery 87.

Terminal block 46 which is mounted at the operators station asillustrated in FIGS. 1 and 2, mounts three double throw, double poleswitches 88, 89, 91 each of which is connected to the electrical sourceby supply lead 92.

Referring to FIGS. 3, 4, and 6, the operation of the control system willnow be explained. Hydraulic fluid supplied by pump 53 to supply conduit54 passes through the open center bowl and apron control valves 96, 97,which together make up valve assembly 41. After passing through controlvalves 96, 97 the fluid continues to port 98 in the opposite wall of thevalve housing 99, thence into the segment of passage 54 shown at thebottom of FIG. 4. When the operator wishes to raise the bowl structure18, he pushes double pole switch 88 upwardly,

' as viewed in FIG. 3, to engage contacts 101, 102 thereby energizingair valves 103, 81 through flow of electricity thereto through leads106, 107. Upon energizing of air control valve 103, air is supplied to achamber, not shown, at the end of the bowl control spool 108 and thelatter will be moved to the left, as viewed in FIG. 4, thereby supplyinghydraulic pressure fluid to port 109 which is connected through a Tconnection 111 to hoses 112, 113 leading to the lower rod end ofhydraulic jacks 32. When the double pole switch 88 is moved to a bowlraising position as just described, the air valve 81 admits air fromconduit 82 to the chamber 116 at the end of a dumping valve spool 117thereby moving the latter downwardly as viewed in FIG. 6 against theaction of spring 118 to a position wherein land 119 blocks port 121 toprevent escape of supply fluid through conduit 58 to the reservoir 49 towhich port 122 of the valve housing 123 is connected. Relief valve 61 isof the diflerential pressure type and is set at an appropriate pressureto guard the pump against excessive pressures. The diverter valve 48 andrelief valve 61 are connected hydraulically in parallel between thereservoir 49 and the high pressure side of the system. When the rod endsof the jacks 32 are being supplied with pressure fluid, the oppositeends of the jacks are being exhausted to permit contraction and theexhausted fluid ,moves from the upper end of the jack through conduits131, 132, to a T connection 133, thence through port 134 in valvehousing 99'to the low pressure cavity 136 in the valve housing to whichbranch return passage 57'is connected.

When the double pole switch 88 is moved to its bowl lowering position,contacts 141,142 are engaged and air control valves 143 and 81 areenergized -by current supplied through lead 144 and 146, respectively.The bowl structure 18 is thus lowered through expansion of hydraulicjacks 32. Cavitation is prevented by anti-cavitation of valve 147, asillustrated in FIG. 4, should the pump 53 fail to supply fluid at asuflicient rate during lowering of the bowl structure.

When it is desired to raise the apron, double pole switch 89 is moved toengage contacts, 151, 152 thereby energizing air control valves 153, '81through current flow throughleads 154, 163 to eifect supplying hydraulicfluid to jack 36 through hose 162 and to effect closing of the bypasspassage 58. The apron is lowered upon the operator moving the doublepole switch to the upper position, as shown in FIG. 3, wherein contact164' is engaged thereby energizing air control valve 164 by current flowthrough lead 166. In the lowering position of valve spool 159, port 161communicates with return to reservoir chamber 136 and the apron controlvalve 97 remains open through its center.

The ejector jack 31 is expanded to pivot the bowl bottom about its pivotconnection 29 to an ejecting position when double pole switch 91 ismoved downwardly, as viewed in FIG. 3, to engage contacts 171, 182. Uponengaging contact 171, current is supplied to solenoid operated aircontrol valve 172 through lead 173 thereby permitting compressed. air toenter chamber 175 through air conduit 76. Pressurization of chamber 175moves the ejector valve spool 174 to the left as viewed in FIG. 5,thereby causing land 176 to close port 177 and place supply port 178 influid supplying relation to ejector jack supply port 179 which is influid communication-with ejector jack supply hose 181. Supply port 178is connected to supply passage 54. When the switch 91 is moved to theeject position as beforementioned, contact 182 is also engaged causingcurrent to flow through lead 183 to actuate air valve 81 which elfectsclosing of the diverter valve 48.

When it is desired to' contract the ejector jack 31, the double poleswitch 91 is moved upwardly, as shown in 'FIG. 3, to contact terminal184, thus supplying current to solenoid operated air control valve 186through lead 187. When solenoid valve 186 is thus energized, the valveis conditioned to place the air supply conduit 77 in communication withair pressure chamber188 thus causing the valve spool '174 which acts asa piston, to move to the right thereby placing the ejector jacksupplyport 179 in fluid communication with the return to reservoir chamber 189which is in free fluid communication with return passage 56 which isillustrated as a hose.

From the foregoing description, it is seen that the electricallyoperated remote control system of this invention minimizes the hydraulichose requirements for operating a plurality of hydraulic jacks. Thestructure shown within the broken lines 200 is mounted on the trailingunit 16 and the remaining portion of the control system is 'located onthe tractor unit 11. Use of the vehicle compressed air system to actuatethe valves permits an electrio control system to be employed which hassufliciently low power requirements to permit it to be supplied byconventional earth mover electric supply means. By 10- cating thehydraulic control valves near or adjacent to jacks which they control,the jacks will be subject to hydraulic pressure immediately uponactuation of the appropriate switches 88, 89, 91 thus giving fastresponse. The pump unloading means, in the form of bypass conduit 58 anddiverter valve 48, unloads the pump 53 when pressure fluid is notrequired to actuate the jacks. This reduces pump wear as well asreducing power consumption. The relief valve 61 is brought intooperation only when the pressure exceeds the safe operating value foractuation of the jacks. The 'use of open center valves is preferredsince even when the diverter valve 48 is open, a low velocity flow willtake place through such valves thereby reducing flow inertia. Thus uponactuation of a control switch, the response of the jack will be almostinstantaneous. Further, by use of diverter valve 48 and an open centerejector valve 42, fluid may be exhausted from the ejector ram '31 toreservoir not only by way of return to reservoir passage 56, but also byway of bypass passage 58.

Although a single embodiment of this electric over air over hydrauliccontrol system for an earth mover has been illustrated and described, itis not intended to so limit this invention, but rather it is intendedthat this invention shall include such other embodiments and modifications as areembraced by the appended claims.

Having now particularly described and ascertained the nature of our saidinvention and the manner in which it is to be performed, we declare thatwhat we claim is:

1. A control system for a self-propelled earth mover including a bowladjustable between excavating and transport positions by means includinga first hydraulic motor and having means for ejecting material from saidbowl including a second hydraulic motor; a hydraulic control valve foreach of said motors; hose means connecting said valves to said motors,respectively; a hydraulic fluid supply system on said earth moverincluding a pump and a hydraulic reservoir connected in fluid supplyingrelation to said pump; a hydraulic fluid supply passage connecting saidcontrol valves in series to said pump; a return to reservoir passageconnecting said valves to said reservoir; a bypass passage between saidreservoir and said supply passage on the upstream side of said controlvalves; a diverter valve in said bypass passage having open and closedpositions; and electric over air control means for said valves includingan electrically operated air valve attached to each of said control anddiverter valves and manually operated selector switches at the operatorssta tion for selectively operating said air valves, said control meansautomatically moving said diverter valve to a closed position wheneverthe operator moves one of said switches to a motor actuating position.

2. The structure set forth in claim 1 wherein said valves are of theopen center type thereby permitting circulation of low pressurehydraulic fluid through said supply and return to reservoir passageswhen said diverter valve is in its open position.

3. The structure set forth in claim 1 wherein said control valves aremounted on said earth mover adjacent to their associated motors,respectively.

4. In combination with an earth mover having a tractor unit and atrailer unit drawn thereby through hitch means permitting relativepivotal movement of said units about a vertical axis, a bowl on saidtrailer unit, means for adjusting said bowl between excavating andtransport positions including a first hydraulic motor on said trailerunit at the front of said bowl, means for ejecting material from saidbowl including a second hydraulic motor at the rear of said bowl, afirst open center control valve mounted on said trailer unit adjacent tosaid first motor and operatively connected to the latter, a second opencenter control valve mounted on said trailer unit adjacent to saidsecond motor, said first and second valves having hold and motoractuating positions, a hydraulic fluid supply system on said earth moverincluding a pump and a hydraulic reservoir connected in fluid supplyingrelation to said pump, a hydraulic fluid supply passage connecting saidcontrol valves in series to said pump, a return to reservoir passageconnecting said control valves to said reservoir, a bypass passagebetween said reservoir and said supply passage on the upstream side ofsaid control valves, a diverter valve in said bypass passage having openand closed positions, said diverter valve being remote from said controlvalves, remote control means for operating said control valves includingmanually operated elements remote from said control valves havingneutral and motor actuating positions and means for automatical- 1ymoving said diverter valve to a closed position when the operator movesone of said manual control elements to a motor actuating position, fluidsupplied by said pump passing at low pressure to said reservoir throughsaid bypass passage and through said fluid supply passage when saidmotors are not being actuated thereby insuring quick motor response uponmovement of one said manually operated elements to a motor actuatingposition.

5. The structure set forth in claim 4 wherein said remote control meansis an electrically operated remote control system and said manuallyoperated elements are switches.

6. The structure set forth in claim 4 wherein said control valves arepilot operated by fluid pressure controlled by said remote controlmeans.

References Cited by the Examiner UNITED STATES PATENTS 2,214,817 9/40Harrington -52 2,243,364 5/41 Trautman 60-97 X 2,247,140 6/41 Twyman60-97 2,256,051 9/41 Haile 37-126 2,274,527 2/42 Buran 37-126 2,284,4135/42 Frentzel 37-126 X 2,318,851 5/43 Griflith 60-97 X 2,319,551 5/43Linden 60-97 X 2,700,986 2/55 Gunn 251-31 X 2,955,617 10/60 Collins121-157 X 3,068,596 12/62 Hein 37-129 3,089,517 5/63 Ludwig 137-62564FOREIGN PATENTS 1,129,777 9/56 France.

BENJAMIN HERSH, Primary Examiner.

1. A CONTROL SYSTEM FOR A SELF-PROPELLED EARTH MOVER INCLUDING A BOWLAJDUSTABLE BEWTEEN EXCAVATING AND TRANSPORT POSITIONS BY MEANS INCLUDINGA FIRST HYDRAULIC MOTOR AND HAVING MEAN FOR EJECTING MATERIAL FROM SAIDBOWL INCLUDING A SECOND HYDRAULIC MOTOR; A HYDRAULIC CONTROL VALVE FOREACH OF SAID MOTORS; HOSE MEANS CONNECTING SAID VALVES TO SAID MOTORS,RESPECTIVELY; A HYDRAULIC FLUID SUPPLY SYSTEM ON SAID EARTH MOVERINCLUDING A PUMP AND A HYDRAULIC RESEVOIR CONNECTED IN FLUID SUPPLYINGRELATIN TO SAID PUMP; A HYDRAULIC FLUID SUPPLY PASSAGE CONNECTION SAIDCONTROL VALVES IN SERIES TO SAID PUMP; A RETURN TO RESERVOIR PASSAGECONNECTING SAID VALVES TO SAID RESERVOIR; A BYPASS PASSAGE BETWEEN SAIDRESERVOIR AND SAID SUPPLY PASSAGE ON THE UPSTREAM SIDE O SAID CONTROLVALVES; A DIVERTER VALVE IN SAID BYPASS PASSAGE HAVING OPEN AND CLOSEDPOSITIONS; AND ELECTRIC OVER AIR CONTROL MEANS FOR SAID VALVES INCLUDINGAN ELECTRICALLY OPERATED AIR VALVE ATTACHED TO EACH OF SAID CONTROL ANDDIVERTER VALVES AND MANUALLY OPERATED SELECTOR SWITCHES AT THEOPERATOR''S STATION FOR SELECTIVELY OPERATING SAID AIR VALVES, SAIDCONTROL MEANS AUTOMATICALY MOVING SAID DIVERTER VALVE TO A CLOSEDPOSITIN WHENEVER THE OPERATOR MOVES ONE OF SAID SWITCHES TO A MOTORACTUATING POSITION.